title: Heifer teats sprayed in the dry period with an iodine teat sanitizer have reduced Streptococcus uberis teat-end contamination and less Streptococcus uberis intra-mammary infections at calving.
abstract: Heifers managed under pastoral conditions are at risk from Streptococcus uberis mastitis infections at calving. A total of 397 heifers from six farms around New Zealand were enrolled in a study to identify and enumerate S. uberis on teat-ends of heifers in the peri-partum period, and to understand the effect of teat-spraying in the pre-calving period on the prevalence and incidence of S. uberis mastitis post-calving. Heifers were randomly assigned to Control or Sprayed groups. Sprayed heifers were teat-sprayed once, three times a week (Monday, Wednesday and Friday) with a commercial iodine-based teat sanitizer, starting at 3 weeks prior to calving and ending at day of calving. Across three farms, all glands of cows in both groups were sampled at calving to determine S. uberis intra-mammary infection (IMI) prevalence. For all farms, clinical mastitis (CM) cases detected during the week after calving were sampled and submitted for bacteriological analysis. Swabbing of teat-ends of 54 heifers from one farm showed that heifers had a pre-existing S. uberis contamination averaging 610 colony-forming units per swab (cfu/swab), at 3 weeks prior to calving. At calving, teat-end contamination was 560 cfu/swab for Sprayed heifers and 1775 cfu/swab for Control heifers. Two weeks after calving, teat-end contamination was similar between both groups, at 30 cfu/swab. The prevalence of S. uberis IMI was significantly lower in the Sprayed (3.5% glands) vs. the Control (7.4%) heifers in the first week after calving. There was a trend for Sprayed heifers (3.6% heifers) to have a lower incidence of S. uberis CM compared with Control heifers (7.4% heifers). It is concluded that teat-spraying in the dry period is a management option that could contribute to controlling heifer S. uberis mastitis in the transition period.
authors.affiliation: DairyNZ Ltd., Hamilton, New Zealand.
authors.forename: Mario G
authors.initials: MG
authors.lastname: Lopez-Benavides
authors.forename: John H
authors.initials: JH
authors.lastname: Williamson
authors.forename: S Jane
authors.initials: SJ
authors.lastname: Lacy-Hulbert
authors.forename: Ray T
authors.initials: RT
authors.lastname: Cursons
mesh_terms: D000822:Animal Husbandry; D000818:Animals; D000891:Anti-Infective Agents, Local / Q000008:administration & dosage / Q000627:therapeutic use*; D002417:Cattle; D005260:Female; D007455:Iodine / Q000008:administration & dosage / Q000627:therapeutic use*; D007774:Lactation; D008321:Mammary Glands, Animal / Q000382:microbiology*; D008414:Mastitis, Bovine / Q000188:drug therapy / Q000517:prevention & control*; D013290:Streptococcal Infections / Q000188:drug therapy / Q000517:prevention & control / Q000662:veterinary*; D013291:Streptococcus / Q000187:drug effects*
chemical_list: D000891:Anti-Infective Agents, Local; D007455:Iodine